Nasal Positive Pressure Ventilation in Patients with Acute Respiratory Failure (5)
The ICU team judged that criteria for an immediate intubation were present, but that the risk of a bronchopulmonary infection due to a possibly prolonged intubation period was high in this setting of deep immunosuppression. In additiqp, an index of heart graft rejection according to the Texas scale was severe enough (No. 6-7) on a myocardial endovenous biopsy to preclude diminishing immunosuppressive therapy. A trial of NPPV was begun, using a commercial nasal mask (Respironics) and a positive-pressure ventilator (Bennett Companion 2000) designed for long-term home ventilation, whose settings are described in Table 1.
Immediately, dyspnea disappeared, as well as tachycardia and arterial hypertension; arterial blood gas levels were easily corrected, and the patient, who previously had been completely exhausted, fell asleep and was apneic, with the mechanical respirator apparently performing the entire inspiratory work (no “trigger” signal on the pressure monitor of the ventilator). As seen in Figure 1, NPPV was performed during 20 hours of the first day, after which its duration was progressively decreased and finally stopped after eight days, when the VC was greater than 2 L; this improvement may be due to the association of inspiratory muscle rest due to NPPV and improvement of muscle weakness induced by a new series of plasmaphereses.